[go] backport [C++] ninja file regeneration rules

1 files changed, 101 insertions, 16 deletions

diff --git a/ninja.go b/ninja.go
index 45de622..1203376 100644
--- a/ninja.go
+++ b/ninja.go
@@ -28,10 +28,16 @@ import (
 
 // NinjaGenerator generates ninja build files from DepGraph.
 type NinjaGenerator struct {
+	// Args is original arguments to generate the ninja file.
+	Args []string
+	// Suffix is suffix for generated files.
+	Suffix string
 	// GomaDir is goma directory.  If empty, goma will not be used.
 	GomaDir string
 	// DetectAndroidEcho detects echo as description.
 	DetectAndroidEcho bool
+	// ErrorOnEnvChange cause error when env change is detected when run ninja.
+	ErrorOnEnvChange bool
 
 	f       *os.File
 	nodes   []*DepNode
@@ -447,16 +453,85 @@ func (n *NinjaGenerator) emitNode(node *DepNode) error {
 	return nil
 }
 
-func (n *NinjaGenerator) shName(suffix string) string {
-	return fmt.Sprintf("ninja%s.sh", suffix)
+func (n *NinjaGenerator) emitRegenRules() error {
+	if len(n.Args) == 0 {
+		return nil
+	}
+	mkfiles, err := n.ctx.ev.EvaluateVar("MAKEFILE_LIST")
+	if err != nil {
+		return err
+	}
+	fmt.Fprintf(n.f, `
+rule regen_ninja
+ description = Regenerate ninja files due to dependency
+ generator=1
+ command=%s
+`, strings.Join(n.Args, " "))
+	fmt.Fprintf(n.f, "build %s: regen_ninja %s", n.ninjaName(), mkfiles)
+	// TODO: Add dependencies to directories read by $(wildcard) or
+	// $(shell find).
+	if len(usedEnvs) > 0 {
+		fmt.Fprintf(n.f, " %s", n.envlistName())
+	}
+	fmt.Fprintf(n.f, "\n\n")
+	if len(usedEnvs) == 0 {
+		return nil
+	}
+	fmt.Fprint(n.f, `
+build .always_build: phony
+rule regen_envlist
+ description = Check $out
+ generator = 1
+ restat = 1
+ command = rm -f $out.tmp`)
+	for env := range usedEnvs {
+		fmt.Fprintf(n.f, " && echo %s=$$%s >> $out.tmp", env, env)
+	}
+	if n.ErrorOnEnvChange {
+		fmt.Fprintln(n.f, " && (cmp -s $out.tmp $out || (echo Environment variable changes are detected && diff -u $out $out.tmp))")
+	} else {
+		fmt.Fprintln(n.f, " && (cmp -s $out.tmp $out || mv $out.tmp $out)")
+	}
+
+	fmt.Fprintf(n.f, "build %s: regen_envlist .always_build\n\n", n.envlistName())
+	return nil
+}
+
+func (n *NinjaGenerator) shName() string {
+	return fmt.Sprintf("ninja%s.sh", n.Suffix)
+}
+
+func (n *NinjaGenerator) ninjaName() string {
+	return fmt.Sprintf("build%s.ninja", n.Suffix)
 }
 
-func (n *NinjaGenerator) ninjaName(suffix string) string {
-	return fmt.Sprintf("build%s.ninja", suffix)
+func (n *NinjaGenerator) envlistName() string {
+	return fmt.Sprintf(".kati_env%s", n.Suffix)
 }
 
-func (n *NinjaGenerator) generateShell(suffix string) (err error) {
-	f, err := os.Create(n.shName(suffix))
+func (n *NinjaGenerator) generateEnvlist() (err error) {
+	f, err := os.Create(n.envlistName())
+	if err != nil {
+		return err
+	}
+	defer func() {
+		cerr := f.Close()
+		if err == nil {
+			err = cerr
+		}
+	}()
+	for k := range usedEnvs {
+		v, err := n.ctx.ev.EvaluateVar(k)
+		if err != nil {
+			return err
+		}
+		fmt.Fprintf(f, "%s=%s\n", k, v)
+	}
+	return nil
+}
+
+func (n *NinjaGenerator) generateShell() (err error) {
+	f, err := os.Create(n.shName())
 	if err != nil {
 		return err
 	}
@@ -471,6 +546,9 @@ func (n *NinjaGenerator) generateShell(suffix string) (err error) {
 	fmt.Fprintf(f, "# Generated by kati %s\n", gitVersion)
 	fmt.Fprintln(f)
 	fmt.Fprintln(f, `cd $(dirname "$0")`)
+	if n.Suffix != "" {
+		fmt.Fprintf(f, "if [ -f %s ]; then\n export $(cat %s)\nfi\n", n.envlistName(), n.envlistName())
+	}
 	for name, export := range n.exports {
 		if export {
 			v, err := n.ctx.ev.EvaluateVar(name)
@@ -483,16 +561,16 @@ func (n *NinjaGenerator) generateShell(suffix string) (err error) {
 		}
 	}
 	if n.GomaDir == "" {
-		fmt.Fprintf(f, `exec ninja -f %s "$@"`+"\n", n.ninjaName(suffix))
+		fmt.Fprintf(f, `exec ninja -f %s "$@"`+"\n", n.ninjaName())
 	} else {
-		fmt.Fprintf(f, `exec ninja -f %s -j500 "$@"`+"\n", n.ninjaName(suffix))
+		fmt.Fprintf(f, `exec ninja -f %s -j500 "$@"`+"\n", n.ninjaName())
 	}
 
 	return f.Chmod(0755)
 }
 
-func (n *NinjaGenerator) generateNinja(suffix, defaultTarget string) (err error) {
-	f, err := os.Create(n.ninjaName(suffix))
+func (n *NinjaGenerator) generateNinja(defaultTarget string) (err error) {
+	f, err := os.Create(n.ninjaName())
 	if err != nil {
 		return err
 	}
@@ -526,7 +604,12 @@ func (n *NinjaGenerator) generateNinja(suffix, defaultTarget string) (err error)
 
 	if n.GomaDir != "" {
 		fmt.Fprintf(n.f, "pool local_pool\n")
-		fmt.Fprintf(n.f, " depth = %d\n", runtime.NumCPU())
+		fmt.Fprintf(n.f, " depth = %d\n\n", runtime.NumCPU())
+	}
+
+	err = n.emitRegenRules()
+	if err != nil {
+		return err
 	}
 
 	// defining $out for $@ and $in for $^ here doesn't work well,
@@ -558,16 +641,18 @@ func (n *NinjaGenerator) generateNinja(suffix, defaultTarget string) (err error)
 		}
 		fmt.Fprintf(n.f, "build %s: phony %s\n", name, n.shortNames[name][0])
 	}
-	// TODO(ukai): regenerate build.ninja when Makefile or dir used for
-	// wildcard is newer than build.ninja?
 	return nil
 }
 
 // Save generates build.ninja from DepGraph.
-func (n *NinjaGenerator) Save(g *DepGraph, suffix string, targets []string) error {
+func (n *NinjaGenerator) Save(g *DepGraph, name string, targets []string) error {
 	startTime := time.Now()
 	n.init(g)
-	err := n.generateShell(suffix)
+	err := n.generateEnvlist()
+	if err != nil {
+		return err
+	}
+	err = n.generateShell()
 	if err != nil {
 		return err
 	}
@@ -575,7 +660,7 @@ func (n *NinjaGenerator) Save(g *DepGraph, suffix string, targets []string) erro
 	if len(targets) == 0 && len(g.nodes) > 0 {
 		defaultTarget = g.nodes[0].Output
 	}
-	err = n.generateNinja(suffix, defaultTarget)
+	err = n.generateNinja(defaultTarget)
 	if err != nil {
 		return err
 	}